Multiple electrode arrangement for producing a diffused electrical discharge



Jan. 28, 1964 F. 1.. WATTENDORF ETAL 3,119,233

MULTIPLE ELECTRODE ARRANGEMENT FOR PRODUCING A DIFFUSED ELECTRICAL DISCHARGE Filed Jan. 18, 1962 I5 coouue GAS 20 l7.

SUPPLY e T W T 3127 //1 Pig-E INVENTORS FRANK L.WATTENDORF HANS J P VON OHAIN y MAURICE' .LAWSON ATTORNEY AGENT United States Patent MULTIPLE ELECTRUDE ARRANGEMENT FOR PRQDUCING A DHFFUSED ELECTRICAL DIS- CHARGE Frank L. Wattendorf, 43 W. Riverview, Dayton, Ohio,

Hans J. P. Von Ohain, 10691 Wolf Creek Pike, Brookville, ()hio, and Maurice 0. Lawson, 119 Rubicon Road, Dayton 9, (lhio Filed Jan. 18, 1962, Ser. No. 167,201 5 Claims. (Ci. 6l)35.5)

(Granted under Title 35 US. Code (1952), see. 266) This invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to us of any royalty thereon.

The invention relates to a device for adding energy to the gas flow in an expansion nozzle.

One object of the invention is to supply energy to a gas which may be used for the expansion of the flow to higher velocities such as for use in a wind tunnel or rocket nozzle.

This and other objects will be more fully understood from the following description taken with the drawing wherein:

FIG. 1 is a schematic view of an electrode arrangement for adding energy to a gas flow in a nozzle; and

FIG. 2 is a modification of the device of FIG. 1 using a center electrode.

When a gas is expanded in a nozzle to provide higher velocity flow, the accompanying decrease in temperature is sometimes undesirable. Energy can be added to the gas to prevent this temperature drop by providing a large number of sharply pointed electrodes located over the length of the nozzle and by supplying the electrodes with high voltage alternating or pulsating electrical energy. The corona discharge around the electrodes ionizes the gas and thus adds energy to it. Cold gas is supplied around each electrode to provide cooling.

Referring more particularly to FIG. 1 of the drawing, reference number It) refers to a flow duct or nozzle made of a ceramic or other suitable material capable of withstanding high temperature to which gas at or near sonic velocity is supplied from a source indicated schematically at 11. The gas from the supply 11 should have a pressure of at least one atmosphere and may be at room temperature or it may be preheated depending upon its use. Expansion of the gas within the nozzle provides gas at supersonic velocities to leave the outlet of the nozzle at 12. Energy is added to the gas within the nozzle 10 by means of a plurality of sharply pointed electrodes 13 and 14 which are located along the length of nozzle 16). Alternating or pulsating electrical energy from a high voltage supply 15 is applied to electrodes 13 and 14 through condenser elements 16 and over leads 17a and 17b. The voltage used must be sufiicient to provide a corona discharge from electrodes 13 and 14 with the voltage used being determined by the pressure of the gas within nozzle 10. The condenser elements are current limiting impedance elements which are used to assure distribution of the discharge over all of the electrodes. Inductance elements can be substituted for the condensers if desired.

Cooling of electrodes 13 and 14 and nozzle 1% is provided by means of cold gas entering the nozzle 10 through openings 1% around the electrodes 13 and 14 from a cold gas supply indicated schematically at 215.

A diffuse corona electrical discharge from the high voltage electrodes 13 and 14 ionizes the gas within the nozzle 10 and thus adds energy to the gas. By adding the energy to the gas by means of a plurality of electrodes spaced along the nozzle, the energy addition can take place over the length of the tube during the expansion of the gas so 3,119,233 Patented Jan. 28, 1964 ICC that exceedingly high static gas temperature can be avoided, such as in an arc discharge. The electrodes 13 and 14 need not be located in a straight line from one end of the nozzle to the other but may be located in a preselected pattern around the nozzle.

While the device of FIG. 1 shows the power supply connected between the electrodes 13 and the electrodes 14, a center electrode 23 may be used as shown in FIG. 2 with the power supply being connected between the center electrode 23 and electrodes 24. All of the other structure which is the same as FIG. 1 have been given like reference numbers.

Various additional processes which may be used with the gases leaving the nozzle 12 will occur to those skilled in the art. Some of these are, further expansion during the recombination of the charged particles, further energy addition by high frequency alternating currents, further energy addition by magnetohydrodynamic effects employing either traveling magnetic fields or instantaneous chilling for the production of chemical compounds.

There is thus provided a device for supplying energy to a gas which is expanded to higher velocities in a nozzle.

While certain specific embodiments have been described in detail, it is obvious that numerous changes may be made without departing from the general principle and scope of the invention.

We claim:

1. A device for supplying energy to a high velocity gas comprising, a high velocity expansion nozzle, means for supplying gas at near sonic velocity to said nozzle, a plurality of circumferentially spaced openings in the nozzle wall spaced along the length of said nozzle, a sharply pointed electrode extending into each of said openings, means for suplying cooling gas to said nozzle through said openings around said electrodes and means for providing a corona discharge from said electrodes to thereby supply energy to said gas.

2. A device for supplying energy to a high velocity gas comprising, a high velocity expansion nozzle, means for supplying gas at near sonic velocity to said nozzle, a plurality of openings in the nozzle wall spaced along the length of said nozzle, a sharply pointed electrode extending into each of said openings, means for supplying cooling gas through said openings around said electrodes into said nozzle and means for applying a high alternating voltage to said electrodes.

3. A device for supplying energy to a high velocity gas comprising, a high velocity expansion nozzle, a chamber surrounding said nozzle, means for supplying gas at near sonic velocity to said nozzle, a plurality of openings in the nozzle wall spaced along the length of said nozzle, a sharply pointed electrode extending into each of said openings, means for supplying cooling gas through said openings around said electrodes into said nozzle and means for applying a high alternating voltage to said electrodes.

4. A device for supplying energy to a high velocity gas comprising, a high velocity expansion nozzle, means for supplying gas at near sonic velocity to said nozzle, a plurality of openings in the nozzle wall spaced along the length of said nozzle, a sharply pointed electrode extending into each of said openings, means for supplying cooling gas through said openings around said electrodes into said nozzle, a central electrode within said nozzle and means for applying a high alternating voltage between said sharply pointed electrodes and said central electrode.

5. A device for supplying energy to a high velocity gas comprising, a high velocity expansion nozzle, a chamber surrounding said nozzle, means for supplying gas at near sonic velocity to said nozzle, a plurality of openings in the nozzle wall spaced along the length of said nozzle,

a sharply pointed electrode extending into each of said openings, means for supplying cooling gas through said openings around said electrodes into said nozzle, a central electrode Within said nozzle and means for applying a high alternating voltage between said sharply pointed electrodes and said central electrode, and a high impedance means connected in the circuit between said voltage applying means and each of said pointed electrodes.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A DEVICE FOR SUPPLYING ENERGY TO A HIGH VELOCITY GAS COMPRISING, A HIGH VELOCITY EXPANSION NOZZLE, MEANS FOR SUPPLYING GAS AT NEAR SONIC VELOCITY TO SAID NOZZLE, A PLURALITY OF CIRCUMFERENTIALLY SPACED OPENINGS IN THE NOZZLE WALL SPACED ALONG THE LENGTH OF SAID NOZZLE, A SHARPLY POINTED ELECTRODE EXTENDING INTO EACH OF SAID OPENINGS, MEANS FOR SUPPLYING COOLING GAS TO SAID NOZZLE THROUGH SAID OPENINGS AROUND SAID ELECTRODES AND MEANS FOR PROVIDING A CORONA DISCHARGE FROM SAID ELECTRODES TO THEREBY SUPPLY ENERGY TO SAID GAS. 